A catalytic antioxidant for limiting amyloid-beta peptide aggregation and reactive oxygen species generation† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c8sc04660c

An Fe corrole is shown to bind to the amyloid-beta peptide and limit reactive oxygen species generation and peptide aggregation of relevance to Alzheimer's disease. Alzheimer's disease (AD) is a multifaceted disease that is characterized by increased oxidative stress, metal-ion dysregulation, and the formation of intracellular neurofibrillary tangles and extracellular amyloid-β (Aβ) aggregates. In this work we report the large affinity binding of the iron( iii ) 2,17-bis-sulfonato-5,10,15-tris(pentafluorophenyl)corrole complex FeL1 to the Aβ peptide ( K d ∼ 10 –7 ) and the ability of the bound FeL1 to act as a catalytic antioxidant in both the presence and absence of Cu( ii ) ions. Specific findings are that: (a) an Aβ histidine residue binds axially to FeL1 ; (b) that the resulting adduct is an efficient catalase; (c) this interaction restricts the formation of high molecular weight peptide aggregates. UV-Vis and electron paramagnetic resonance (EPR) studies show that although the binding of FeL1 does not influence the Aβ–Cu( ii ) interaction ( K d ∼ 10 –10 ), bound FeL1 still acts as an antioxidant thereby significantly limiting reactive oxygen species (ROS) generation from Aβ-Cu. Overall, FeL1 is shown to bind to the Aβ peptide, and modulate peptide aggregation. In addition, FeL1 forms a ternary species with Aβ–Cu( ii ) and impedes ROS generation, thus showing the promise of discrete metal complexes to limit the toxicity pathways of the Aβ peptide.